Working Method of JVM Rolls With Special Fibre Covering

1. The porous roll surface absorbs the solution (fluid) enabling relief, in spite of pressure, while still keeping the tight contact with the strip.
2. The void volume of the roll is compressed to near zero at the nip centre, creating a seal which is restored with each revolution of the roll.
3. The porous roll surface reopens when the compression decreases. This sponge-like function removes residual moisture from the strip.

Operation Mode of Rolls Under Pressure

In the working process the roll is squeezed together, i.e. pressure is applied to it. In contrast to JVM Rolls, rubber and polyurethane coated rolls are prone to substantial plastic deformation.

This leads to a distortion of the coating in the work area (nip) of the rolls. The contact pressure, which is adjusted by hydraulic or pneumatic cylinders, causes tensions in the surface of the rubber or the polyurethane coating.

This is due to the porosity of the JVM special fibre covering (figure above). Under pressure, the JVM covering is able to increase in density in the compressed (nip) area without changing its general circular form. In this way, the JVM Roll stays in constant contact with the strip.